How to Enable Registry Keys for Delivery Restrictions


The default setting allows everyone in your organization to use the SMTP connector. In most situations, the default setting is sufficient because you generally want your users to be able to send Internet mail. If you want to set more rigid restrictions, use the following procedure and How to Set Delivery Restrictions on the SMTP Connector to set delivery restrictions.

You can use the Delivery tab to restrict the use of your connector. However, to enable these restrictions, you must also change certain registry key settings.


Be aware that restricting delivery is extremely process-intensive and can affect server performance.

A registry key on the Exchange Server 2003-based bridgehead server, which is the source for the connector that is being checked, controls the restriction-checking functionality. If you need to configure a connector to restrict who can send data to the designated link, you must manually add the restriction-checking registry value.


Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.

Before You Begin

Before you perform the procedure in this topic, read Connecting Exchange to the Internet and How to Set Delivery Restrictions on the SMTP Connector.

The following permissions are required to perform this procedure:

  • Member of the local administrators group


To enable the registry keys for delivery restrictions

  1. Start Registry Editor: From a command prompt, type Regedit.exe.

  2. Navigate to and select the following key in the registry:


  3. On the Edit menu, click Add Value, and then add the following registry value:

    Value Name: CheckConnectorRestrictions
    Data Type: REG_DWORD
    Date: 1
    Radix: Decimal
  4. Exit Registry Editor: On the Registry menu, click Exit.

  5. After enabling the registry key setting, you need to restart the following services on your Exchange server:

    • Microsoft Exchange MTA Stacks (MSExchangeMTA)

    • Microsoft Exchange Routing Engine (RESvc)

    • Simple Mail Transfer Protocol (SMTPSVC)